The present invention concerns more precisely a floating offshore facility for offshore hydrocarbon production.
For the production of hydrocarbon from deep water wells, a tension leg platform (TLP) can be used. A TLP is a floating structure tethered to the seafloor so as to eliminate the heave movement of the structure. The wells drilled into the seafloor are linked to production equipments situated above the floating structure via a plurality of production risers (tubes). The valves (trees) are therefore located out of the sea water inside the dry environment of the floating facility. Thanks to these dry trees, the maintenance on the wells as well as the well interventions are made easier.
Some TLP can accommodate a drilling rig to drill and complete the wells and to perform maintenance operations required inside the wells.
It is known to provide a drilling rig which can be moved over the upper deck to be brought to at least two different positions on the floating facility. It is therefore possible to drill a plurality of wells from the facility, said wells being separated from each other of a predetermined maximum distance.
According to a used method, the drilling riser and blow out preventer device that is installed at a first position are disconnected and removed to install them at a second position. However, this method takes a lot of time and is costly.
According to another method, the facility is equipped with two drilling risers and two blow out preventer devices. However, these equipments are costly.